1. Field of the Invention
This invention relates to a nozzle touch device in an injection molding apparatus which is suited for a compact electric type injection molding apparatus.
2. Related Background Art
In an injection molding apparatus particularly an injection molding apparatus having a hot runner, when a material to be molded in a heating cylinder is to be injected from a nozzle at the end of the cylinder into a metal mold, the nozzle is urged against the entrance of the runner portion of the metal mold so that the molten material to be molded will not leak through the nozzle.
An injection molding apparatus according to the prior art is shown in FIG. 9 of the accompanying drawings. The injection molding apparatus shown in the figure is constructed as a horizontal type apparatus, and comprises chiefly a bed 51, an injection unit 52 on the bed 51, a mold clamping mechanism 53, and a driving hydraulic cylinder 62 holding the injection unit 52 by means of a slide base 54 and moving the slide base in parallel to the injection unit 52. The injection unit 52 is provided with a heating cylinder 55 containing a screw (not shown) therein, a drive source 63 for measurement and blending connected to the rear of the heating cylinder 55, and a drive source 56 for injection. Resin material charged from a hopper 57 into the heating cylinder is blended by the rotation of the screw and is gradually accumulated in front of the screw and injected from a nozzle 58. The mold clamping mechanism 53 is provided with a fixed side mold 59 fixed to the rising portion of the bed 51, and a movable side mold 60 for effecting the opening and closing movement of the mold relative to the mold 59 by a drive source 64.
To effect nozzle touch in this apparatus, the entire injection unit 52 is moved from the hydraulic cylinder 62 and the nozzle 58 is urged against the runner entrance recess 61 of the mold 59 to thereby accomplish nozzle touch.
However, the nozzle touch mechanism of the prior-art injection molding apparatus as described above is of such a construction that the entire injection unit 52 is moved relative to the fixed side mold 59, and this has led to the problem that the driving hydraulic cylinder 62 becomes bulky.
On the other hand, we have devised an electric type injection molding apparatus which, as compared with the prior-art injection molding apparatus, is compact and slim and can also be vertically installed.
However, a conventional nozzle touch mechanism, when mounted on such electric type injection molding apparatus, makes the apparatus bulky and therefore, a novel nozzle touch mechanism suited for an injection molding apparatus constructed compactly and slimly has been desired.